There has been a fair amount of work in this area, mainly for marine
species. You can find quite a bit in the archaeomalacology literature that
has applications to modern faunas. I would recommend this paper:

Zuschin, M., Stachowitsch, M. & Stanton, R. J. (2003) Patterns and processes
of shell fragmentation in modern and ancient marine environments. Earth
Science Reviews 63, 33-82.

This is also a good entry point for the literature in this area of research.
Let me know if you want a .pdf of the paper and I'll send.

Hope this helps

Regards
Alex

-----Original Message-----
From: Conchologists List [mailto:[log in to unmask]] On Behalf Of
David Kirsh
Sent: 09 February 2008 07:37
To: [log in to unmask]
Subject: [CONCH-L] study of worn shells

Does anyone know whether there has been much study of the common ways
that shells are eroded or broken?

I've noticed that I can be walking on an Atlantic beach with someone
who doesn't seriously collect and they'll pick up a (to them)
attractive fragment and I'll know from a small sliver what it is. (But
I might not be able to explain how I know). How many ways are there for
Neverita duplicata to be eroded and broken and sliced by waves and
other environmental factors? It seems like there are quite a few
"forms." It can be challenging to identify certain atypical fragments
or eroded shells of less familiar species.

Some shells are known mainly in their incomplete state. For instance,
they might be invariably "decapitated" by the time they're adult. In
such cases, we're unfamiliar with what they would look like intact.
Just yesterday, I found a young Truncatella with its protoconch intact
and I'm hoping to post an image of that soon.

David Kirsh
Durham, NC

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